1. Field of the Invention
The invention relates to new and improved push-button assemblies.
2. Description of the Prior Art
Certain applications for push buttons are more severe than others, such as those used as elevator car call buttons in an elevator car, and elevator hall call buttons in the hallways of a building. These push buttons are subjected to constant usage by the public, and thus they must be built to withstand intense service. They are also subjected to considerable abuse, both intentional and unintentional. Thus, they must be constructed such that they do not invite vandalism, such as by eliminating visible fastening devices. Further, they must be constructed such that they will withstand abuse and vandalism, such as by being able to withstand actuation by an umbrella point, and extreme closing pressures, without external or internal damage.
Elevator push buttons have still additional requirements which set them apart from the average push button use. They must notify the sighted population that a call has been entered, by illuminating a predetermined portion of the push button after actuation, and the illumination must be maintained until the call is answered. It is also desirable to construct elevator push buttons such that they may be easily used by the visually handicapped.
In addition to reducing the number of service calls by constructing the push buttons to withstand high usage, abuse, and vandalism, they should be constructed to be easily and quickly serviced when service is necessary. For example, the light source in the push button, or any other element thereof, must be easily and quickly replaceable by authorized personnel without the necessity of using special tools.
Elevator systems are currently being constructed with conventional electromechanical relays in the control, with lower voltage solid-state devices, or with combinations of the two. It would be desirable to construct the elevator push buttons in a modular manner such that they are assembled from completely interchangeable "building blocks," enabling high voltage light sources, such as neon lamps, to be used, or low voltage light sources, such as light emitting diodes (LEDS).
Regardless of the light source utilized, the resulting push-button structure must provide adequate illumination when actuated, to notify the user that the call has been entered.
While all of the above requirements place stringent demands on the structure and design of elevator push-button assemblies, these requirements must be met with an assembly which is economically attractive, i.e., it must be easily manufactured of low cost components, and it must be susceptible to quick and accurate assembly without requiring special skills or exacting labor.